Permanent Magnet DC motor Armature Parts of the

Permanent Magnet DC motor

Armature Parts of the DC motor Field magnets Commutator Brushes Axle (shaft)

The field magnets • Usually permanent. • Creates a magnetic field. N S

Armature Coils of wire. Wrapped around a laminated iron core. Creates a magnetic field that interacts with field magnets. N S

Brushes • Transfer electricity from battery to commutator

Commutator • Provides a means of changing electrical contact from 1 armature section to another.

Electromagnetism • A magnetic field surrounds ALL wires that carry electricity (current) • The direction of field rotation is determined by the direction of current through the wire.

Left hand rule for magnetism Thumb points in direction of electron current (- to +) Fingers indicate magnetic field rotation. Field rotates from N to S.

Magnetic fields Emanate from the N pole & move toward the S pole N S

Magnetic Interaction Current moving away: like feathers on an arrow N Current moving toward: like the point of an arrow S Armature wire Permanent Magnet

Magnetic field interaction Rotation of the field opposes the permanent field Decreases the total field on the top Left hand rule N Rotation of the field aides the permanent field Increases the total field on the bottom S

Armature rotation This part rotates up N S This part rotates down

Motor rotation

Continuing the rotation As armature rotates So does commutator Which creates a “new” magnetic field